Improvement in speaking-tube annunciators



R. MAY. Improvement in Speaking-Tube Annunciators.. No.128,552. Cgw-PatentedJu|y2,1s72.

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ROBERT MAY, oE NEw YORK, N. Y.

Specification forming part of Letters Patent No. 128,552, dated July 2,1872.

Specification describin ga new and Improved Speaking Tube Annunciator,invented by erltoRER'r MAY, of New York city, in the county ltd State ofNew York. Y I Figure l represents a face view, partly in secbtion, of myimproved speaking-tube annun- Fig. 2 is a vert-ical transverse sectionnSthe same on the line c c, Fig. 3. Fig. 3 is a vertical section on theline k k,'Fig. 2. Fig. 4 is a detailtransverse section of amodification.

Similar letters of reference indicate corresponding parts. l

This invention relates to an improved mechanism,`whic`n, when connectedwith a speaking-tube, will constitute an index and annunciator to callan attendant and show at which tube response is required.

The invention consists in combining a dropball or swinging-plate, whichis set in motion by air blown through the speaking-tube, with a balancedlever, which serves to establish electric connection when moved by thedis# placement of said ball or plate.

A in the drawing represents one end of a speaking-tube closed by ahiugedplate, B.v A lug, a', projecting from this plate iits,when the plate isclosed, through an upright slide or rod, b, or under a shoulder of thesame, and serves to hold the same elevated. When, by blowing into thetube from above, the plate B is swung slightly open it will withdraw thelug a from the slide b and cause the latter to drop upon a rod, C, thatis attached to a crank, d, of a rock-shaft, D. Vhen the slide b is heldelevated by the lug a the rod C is in contact with its lower end, asshown in Fig. 2. A crank, e, on the opposite side of the shaft D is thenbelow and out of contact with a fixed metal plate, f. When, however, theshaft D is swung by the dropping of the slide b, its arme will bebrought in contact with f, thereby establishing metallic connectionbetween two electric conductors, g g, the circuit through which will setan annunciator or sounding apparatus in motion to call an attendant. Therod O dropped will be an index to the tube to be responded to. The sameresult can be at tained by connecting the rod C by a string, h, with aball or plug, E,which is inserted in the end of tube A, and which whendropped out by the action of air blown into the tube will by its weightcarry the rod (l down, and furthermore, form a .conspicuous indicator.

In hotels or other large establishments,where a considerable number ofspeaking-tubes are conducted to one porters or other room, thisinvention will be4 of great value. It dispenses entirely with the use ofbells and separate annunciator to be operated by the person calling anattendant previous to speaking, and econoinizes thereby considerably inthe outlay for such apparatus.

Several shafts D for a number of speakin gtubes may be arranged in lineunder keys tot' a rock-shaft, F, which when turned by hand will bringits keys z' on the cranks e and restore its disturbed parts to newworkin g position. Fig. 4 shows a modification, according to which adrop-plate, G, at the end of the tube comes in direct contact with thetwo metallic electric conductors m m, and thereby establishes a circuit,its pendent position at the same time indicating the tube to be answeredto.

Having thus described my invention, I claim as new and desire to secureby Letters Patent- 1. The combination o f a drop, b or E, from aspeaking-tube with a crank-shaft, D, and circuit-closing crank thereon,as set forth.

2. The replacing-shaft F and key i thereon, combined with thesubject-matter of the foregoing clause.

3. The drop-plate G, combined with the conductors m m, as set forth.

Witnesses: ROBERT MAY.

GEO. W. MAREE, T. B. MosHER.

